diff --git a/demo/client.ts b/demo/client.ts
index c4befbc8..0cfc6981 100644
--- a/demo/client.ts
+++ b/demo/client.ts
@@ -453,8 +453,6 @@ function initOptions(term: Terminal): void {
     'theme',
     'windowOptions',
     'windowsPty',
-    // Deprecated
-    'fastScrollModifier'
   ];
   const stringOptions = {
     cursorStyle: ['block', 'underline', 'bar'],
diff --git a/src/common/CoreTerminal.ts b/src/common/CoreTerminal.ts
index 90e27a5d..d9c5e8d2 100644
--- a/src/common/CoreTerminal.ts
+++ b/src/common/CoreTerminal.ts
@@ -132,7 +132,7 @@ export abstract class CoreTerminal extends Disposable implements ICoreTerminal {
     this._register(Event.forward(this.coreService.onBinary, this._onBinary));
     this._register(this.coreService.onRequestScrollToBottom(() => this.scrollToBottom(true)));
     this._register(this.coreService.onUserInput(() =>  this._writeBuffer.handleUserInput()));
-    this._register(this.optionsService.onMultipleOptionChange(['windowsMode', 'windowsPty'], () => this._handleWindowsPtyOptionChange()));
+    this._register(this.optionsService.onMultipleOptionChange(['windowsPty'], () => this._handleWindowsPtyOptionChange()));
     this._register(this._bufferService.onScroll(() => {
       this._onScroll.fire({ position: this._bufferService.buffer.ydisp });
       this._inputHandler.markRangeDirty(this._bufferService.buffer.scrollTop, this._bufferService.buffer.scrollBottom);
@@ -255,8 +255,6 @@ export abstract class CoreTerminal extends Disposable implements ICoreTerminal {
     const windowsPty = this.optionsService.rawOptions.windowsPty;
     if (windowsPty && windowsPty.buildNumber !== undefined && windowsPty.buildNumber !== undefined) {
       value = !!(windowsPty.backend === 'conpty' && windowsPty.buildNumber < 21376);
-    } else if (this.optionsService.rawOptions.windowsMode) {
-      value = true;
     }
     if (value) {
       this._enableWindowsWrappingHeuristics();
diff --git a/src/common/buffer/Buffer.ts b/src/common/buffer/Buffer.ts
index 81ab156b..21bb47dc 100644
--- a/src/common/buffer/Buffer.ts
+++ b/src/common/buffer/Buffer.ts
@@ -181,7 +181,7 @@ export class Buffer implements IBuffer {
       if (this._rows < newRows) {
         for (let y = this._rows; y < newRows; y++) {
           if (this.lines.length < newRows + this.ybase) {
-            if (this._optionsService.rawOptions.windowsMode || this._optionsService.rawOptions.windowsPty.backend !== undefined || this._optionsService.rawOptions.windowsPty.buildNumber !== undefined) {
+            if (this._optionsService.rawOptions.windowsPty.backend !== undefined || this._optionsService.rawOptions.windowsPty.buildNumber !== undefined) {
               // Just add the new missing rows on Windows as conpty reprints the screen with it's
               // view of the world. Once a line enters scrollback for conpty it remains there
               this.lines.push(new BufferLine(newCols, nullCell));
@@ -298,7 +298,7 @@ export class Buffer implements IBuffer {
     if (windowsPty && windowsPty.buildNumber) {
       return this._hasScrollback && windowsPty.backend === 'conpty' && windowsPty.buildNumber >= 21376;
     }
-    return this._hasScrollback && !this._optionsService.rawOptions.windowsMode;
+    return this._hasScrollback;
   }
 
   private _reflow(newCols: number, newRows: number): void {
diff --git a/src/common/services/OptionsService.ts b/src/common/services/OptionsService.ts
index 6ad48b93..9203a892 100644
--- a/src/common/services/OptionsService.ts
+++ b/src/common/services/OptionsService.ts
@@ -19,7 +19,6 @@ export const DEFAULT_OPTIONS: Readonly<Required<ITerminalOptions>> = {
   customGlyphs: true,
   drawBoldTextInBrightColors: true,
   documentOverride: null,
-  fastScrollModifier: 'alt',
   fastScrollSensitivity: 5,
   fontFamily: 'monospace',
   fontSize: 15,
@@ -49,7 +48,6 @@ export const DEFAULT_OPTIONS: Readonly<Required<ITerminalOptions>> = {
   rescaleOverlappingGlyphs: false,
   rightClickSelectsWord: isMac,
   windowOptions: {},
-  windowsMode: false,
   windowsPty: {},
   wordSeparator: ' ()[]{}\',"`',
   altClickMovesCursor: true,
diff --git a/src/common/services/Services.ts b/src/common/services/Services.ts
index a2847f1b..1f4b53ce 100644
--- a/src/common/services/Services.ts
+++ b/src/common/services/Services.ts
@@ -234,8 +234,6 @@ export interface ITerminalOptions {
   disableStdin?: boolean;
   documentOverride?: any | null;
   drawBoldTextInBrightColors?: boolean;
-  /** @deprecated No longer supported */
-  fastScrollModifier?: 'none' | 'alt' | 'ctrl' | 'shift';
   fastScrollSensitivity?: number;
   fontSize?: number;
   fontFamily?: string;
@@ -261,7 +259,6 @@ export interface ITerminalOptions {
   smoothScrollDuration?: number;
   tabStopWidth?: number;
   theme?: ITheme;
-  windowsMode?: boolean;
   windowsPty?: IWindowsPty;
   windowOptions?: IWindowOptions;
   wordSeparator?: string;
diff --git a/typings/xterm-headless.d.ts b/typings/xterm-headless.d.ts
index 9c3effda..369de459 100644
--- a/typings/xterm-headless.d.ts
+++ b/typings/xterm-headless.d.ts
@@ -89,13 +89,6 @@ declare module '@xterm/headless' {
      */
     drawBoldTextInBrightColors?: boolean;
 
-    /**
-     * The modifier key hold to multiply scroll speed.
-     * @deprecated This option is no longer available and will always use alt.
-     * Setting this will be ignored.
-     */
-    fastScrollModifier?: 'none' | 'alt' | 'ctrl' | 'shift';
-
     /**
      * The spacing in whole pixels between characters.
      */
@@ -222,25 +215,6 @@ declare module '@xterm/headless' {
      */
     theme?: ITheme;
 
-    /**
-     * Whether "Windows mode" is enabled. Because Windows backends winpty and
-     * conpty operate by doing line wrapping on their side, xterm.js does not
-     * have access to wrapped lines. When Windows mode is enabled the following
-     * changes will be in effect:
-     *
-     * - Reflow is disabled.
-     * - Lines are assumed to be wrapped if the last character of the line is
-     *   not whitespace.
-     *
-     * When using conpty on Windows 11 version >= 21376, it is recommended to
-     * disable this because native text wrapping sequences are output correctly
-     * thanks to https://github.com/microsoft/terminal/issues/405
-     *
-     * @deprecated Use {@link windowsPty}. This value will be ignored if
-     * windowsPty is set.
-     */
-    windowsMode?: boolean;
-
     /**
      * Compatibility information when the pty is known to be hosted on Windows.
      * Setting this will turn on certain heuristics/workarounds depending on the